238 ME. HAMSHAW THOMAS ON THE E0SSIL ELOBA OF [June 1913, 



and have the characteristic auriculate bases. The adjacent pinna? 

 overlap. The apices are bluntly pointed, and the venation is of the 

 usual spreading type. 



These fronds do not differ very much, except in size, from some 

 forms of the commoner species graphicus ; the pinnae are, however, 

 more crowded, are more perpendicular to the rachis, and their 

 apices are blunter. It is probably best, therefore, to distinguish 

 them as a separate species. 



Otozamites graphicus (Leckenby ex Bean MS.). 

 [Q. J. G. S. vol. xx (1864) p. 78 & pi. viii, fig. 5.] 

 The commoner form of Otozamites possesses fronds about 5 cm. 

 broad, with closely-set pinnules. The latter overlap at their bases, 

 which have a well-marked auriculate shape. Their lower margins 

 are markedly curved, while the upper margins are much straighter ; 

 consequently the pinnae do not exhibit so falcate a shape as is usual 

 in this species. The apices are acuminate, and directed slightly 

 forward ; the nervation has the usual spreading character. 



The Marske form is intermediate between 0. graphicus and 

 0. obtusus var. ooliticus Sew. The pinnae bear considerable resem- 

 blance to the latter variety in their shape, but have acuminate 

 apices differing entirely in form from those of 0. obtusus ; the 

 upper lobe of the base is also larger than in the latter. Some of 

 the specimens resemble very closely the example figured by Prof. 

 Seward 1 on pi. ii of the ' Jurassic Flora ' ; but they seem to indicate 

 that the distinction between 0. graphicus and 0. obtusus var. ooliticus 

 is very slight- 

 Other specimens of Otozamites have been found, which are inter- 

 mediate between the above species and certain forms of Ptilo- 

 phyllum (Williamsonia) pecten; the pinnae are narrow, almost 

 straight, and linear-lanceolate. They have acuminate apices and 

 well-marked overlapping auriculate bases. They may possibly 

 belong to a distinct species, but their differences scarcely seem 

 such as to warrant their separation from the above. 



Dicttozamites hawelli Seward. 

 [Q. J. G. S. vol. lix (1903) p. 221.] 

 The collections here described contain a large number of speci- 

 mens of the above species, which is evidently one of the most 

 abundant forms found in this locality. The species was founded in 

 1903 by Prof. Seward on specimens from the Marske Quarry, and 

 there is little to add to the description then given of them. The 

 portions of fronds before me vary in width from 4 to 9 cm., and 

 taper gradually towards the apex. Isolated pinnae are found in 

 the grey shales, and from them good cuticular preparations can be 

 obtained. In these it is seen that the upper epidermis bears no 

 stomata, but consists of cells with very sinuous walls ; the cells 



1 Seward (00) pi. ii, fig. 6. 



